Br Addition Combined with Non-Preheating Method to Prepare Semitransparent Quasi-2D Perovskite Solar Cells with High Average Visible Light Transmittance

Perovskite materials can improve the average visible light transmittance (AVT) of themselves by adjusting the bandgap, which makes them popular for semitransparent photovoltaics (ST-PVs). However, the poor stability of traditional 3D perovskites limits their applications, so we introduce a quasi-two-dimensional perovskite process with better stability for our devices. In this paper, quasi-two-dimensional semitransparent perovskite solar cells (2D-ST-PSCs) with high AVT are prepared by introducing Br- ions to replace some I- ions in BA(2)MA(4)Pb(5)(I1-x Br-x)(16) (x = 0, 0.1, 0.2, 0.3) and combine the nonpreheating (NP) process for the thinner perovskite films. The quasi-two-dimensional perovskite film is created with the advantages of a highly oriented crystal structure, dense morphology, fewer defects, high crystallinity, and uniform particle size distribution when the ideal x value is 0.2. Therefore, the film of the NP process obtains a wide bandgap of 1.75 eV to get a 55.27% AVT. And the device with BA(2)MA(4)Pb(5)(I0.8Br0.2)(16) AVT maintains 44.03%, a power conversion efficiency (PCE) of 7.14%, and a light utilization efficiency (LUE) of 3.14% in complete 2D-ST-PSCs and retains 82% of the initial efficiency after 750 h of storage under 15 +/- 5% RH air conditions.